U.S. patent number 6,824,436 [Application Number 10/213,699] was granted by the patent office on 2004-11-30 for personal watercraft.
This patent grant is currently assigned to Kawasaki Jukogyo Kabushiki Kaisha. Invention is credited to Yoshimoto Matsuda.
United States Patent |
6,824,436 |
Matsuda |
November 30, 2004 |
Personal watercraft
Abstract
Disclosed is a personal watercraft capable of preventing oil
flow from an engine to a breather device. The personal watercraft
comprises: a four-cycle engine; a water jet pump driven by the
engine, the water jet pump pressurizing and accelerating water
taken in from outside of the watercraft and ejecting the water from
the outlet port to propel the watercraft as a reaction of the
ejecting water; a breather pipe configured such that a base end is
connected to the engine to communicate with an inside of the
engine, an intermediate portion is located lower than the base end,
and a tip end is located higher than the base end; and a breather
box, wherein the tip end of the breather pipe communicates with
inside of the breather box and the base end of the breather pipe is
located lower than the breather box.
Inventors: |
Matsuda; Yoshimoto (Kobe,
JP) |
Assignee: |
Kawasaki Jukogyo Kabushiki
Kaisha (Kobe, JP)
|
Family
ID: |
19077043 |
Appl.
No.: |
10/213,699 |
Filed: |
August 6, 2002 |
Foreign Application Priority Data
|
|
|
|
|
Aug 17, 2001 [JP] |
|
|
2001-247783 |
|
Current U.S.
Class: |
440/88A;
123/572 |
Current CPC
Class: |
F01M
13/04 (20130101); F02M 35/10222 (20130101); F01M
11/067 (20130101); F02M 35/168 (20130101); F01M
13/022 (20130101); B63H 11/04 (20130101); F02M
35/10111 (20130101); F01M 11/064 (20130101); B63H
21/386 (20130101); F02M 35/04 (20130101); F02M
35/112 (20130101); F02M 35/167 (20130101); B63B
34/10 (20200201); F02M 35/10013 (20130101); F02B
61/045 (20130101); F02M 25/06 (20130101); Y02T
10/121 (20130101); F01M 2013/0444 (20130101); B63H
21/14 (20130101); Y02T 10/12 (20130101); B63H
21/24 (20130101) |
Current International
Class: |
F01M
13/04 (20060101); F01M 11/00 (20060101); F01M
11/06 (20060101); F01M 13/00 (20060101); F02M
25/06 (20060101); F02B 61/04 (20060101); F02B
61/00 (20060101); F02M 35/02 (20060101); F01M
13/02 (20060101); F02M 35/16 (20060101); F02M
35/00 (20060101); F02M 35/04 (20060101); F02M
35/10 (20060101); F02M 35/104 (20060101); F02M
35/112 (20060101); F01M 013/00 () |
Field of
Search: |
;440/88A,88R
;123/572,41.86,573,574 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wright; Andrew
Attorney, Agent or Firm: Kolisch Hartwell, PC
Claims
What is claimed is:
1. A personal watercraft comprising: a four-cycle engine; a water
jet pump driven by the engine, the water jet pump pressurizing and
accelerating water taken in from outside of the watercraft and
ejecting the water from the outlet port to propel the watercraft as
a reaction of the ejecting water; an air-intake passage provided
for the engine and provided with an air-intake box; a breather box
attached to the air-intake box as a chamber separate from the
air-intake box, the breather box including an oil inlet
communicating with an inside of the engine and an oil return port;
a communicating passage through which the inside of the breather
box communicates with the air-intake passage; a breather pipe
through which the oil inlet of the breather box communicates with
the inside of the engine; and a breather return pipe through which
the oil return port communicates with an oil reservoir.
2. The personal watercraft according to claim 1, wherein an inlet
of the communicating passage extends downwardly from an upper face
of the breather box to protrude into the breather box, the oil
inlet extends upwardly from a bottom face of the breather box to
protrude into the breather box, and a lower end of the inlet of the
communicating passage is located as high as or lower than the oil
inlet.
3. The personal watercraft according to claim 1, wherein the
breather pipe is configured such that a base end connected to the
engine to communicate with the inside of the engine is located
lower than the breather box, a tip end connected to the breather
box to communicate with the inside of the breather box is located
higher than the base end, and an intermediate portion is located
lower than the base end.
4. The personal watercraft according to claim 1, further
comprising: a first baffle wall provided between the oil inlet and
an inlet of the communicating passage in the breather box, the
first baffle wall extending downwardly from a ceiling wall of the
breather box, such that a lower end of the baffle wall is located
lower than an imaginary line connecting an upper end of the oil
inlet to the inlet of the communicating passage so as to form a
space allowing the oil inlet and the inlet of the communicating
passage to communicate with each other below the lower end of the
first baffle wall.
5. The personal watercraft according to claim 4, further
comprising: a second baffle wall provided between the oil inlet and
the inlet of the communicating passage, the second baffle wall
extending vertically from a bottom wall of the breather box, such
that an upper end of the second baffle wall is located higher than
the imaginary line connecting the upper end of the oil inlet to the
inlet of the communicating passage so as to form a space allowing
the oil inlet and the inlet of the communicating passage to
communicate with each other above the upper end of the second
baffle wall.
6. The personal watercraft according to claim 4, wherein the oil
return port is located lower than the oil inlet.
7. The personal watercraft according to claim 4, wherein a throttle
body to control air flow in the air-intake passage is contained in
the air-intake box so that oil mist in the breather box is supplied
to the throttle body through the communicating passage.
8. The personal watercraft according to claim 1, further
comprising: a porous plate provided inside of the breather box, for
permitting flow of oil between the oil inlet and an inlet of the
communicating passage.
9. The personal watercraft according to claim 8, wherein the
breather box is integrally provided inside of the air-intake box
and the communicating passage is formed in a separating wall that
defines the air-intake box and the breather box.
10. The personal watercraft according to claim 8, wherein the oil
return port is located lower than the oil inlet.
11. The personal watercraft according to claim 8, wherein a
throttle body to control air flow in the air-intake passage is
contained in the air-intake box so that oil mist in the breather
box is supplied to the throttle body through the communicating
passage.
12. A personal watercraft comprising: a four-cycle engine; a water
jet pump driven by the engine, the water jet pump pressurizing and
accelerating water taken in from outside of the watercraft and
ejecting the water from the outlet port to propel the watercraft as
a reaction of the ejecting water; an air-intake passage provided
for the engine and provided with an air-intake box; a breather box
provided in the air-intake passage, and including an oil inlet
communicating with an inside of the engine and an oil return port;
a communicating passage through which the inside of the breather
box communicates with the air-intake passage; a breather pipe
through which the oil inlet of the breather box communicates with
the inside of the engine; a breather return pipe through which the
oil return port communicates with an oil reservoir; and a porous
plate provided inside of the breather box, for permitting flow of
oil between the oil inlet and an inlet of the communicating
passage, wherein the breather box is integrally provided at a
bottom of the air-intake box and the communicating passage is
formed in a separating wall that defines the air-intake box and the
breather box.
13. A Personal watercraft comprising: a four-cycle engine; a water
jet pump driven by the engine, the water jet pump pressurizing and
accelerating water taken in from outside of the watercraft and
ejecting the water from the outlet port to propel the watercraft as
a reaction of the ejecting water; an air-intake passage provided
for the engine and provided with an air-intake box; a breather box
provided in the air-intake passage, and including an oil inlet
communicating with an inside of the engine and an oil return port;
a communicating passage through which the inside of the breather
box communicates with the air-intake passage; a breather pipe
through which the oil inlet of the breather box communicates with
the inside of the engine; a breather return pipe through which the
oil return port communicates with an oil reservoir, wherein the
breather pipe has a branch portion at a position lower than a base
end connected to the engine to communicate with the inside of the
engine, and the branch portion communicates with the oil reservoir
of the engine through the oil return pipe.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a jet-propulsion personal
watercraft (PWC) which ejects water rearward and planes on a water
surface as the resulting reaction. More particularly, the present
invention relates to a breather device mounted in an engine.
2. Description of the Related Art
In recent years, so-called jet-propulsion personal watercraft have
been widely used in leisure, sport, rescue activities, and the
like. The jet-propulsion personal watercraft is configured to have
a water jet pump that pressurizes and accelerates water sucked from
a water intake generally provided on a bottom of a hull and ejects
it rearward from an outlet port. Thereby, the personal watercraft
is propelled.
In the jet-propulsion personal watercraft, a steering nozzle
provided behind the outlet port of the water jet pump is swung
either to the right or to the left, to change the ejection
direction of the water to the right or to the left, thereby turning
the watercraft to the right or to the left.
In recent years, the use of a four-cycle engine in the
jet-propulsion personal watercraft has been contemplated.
When the four-cycle engine is mounted in the personal watercraft,
there is a need for a breather device because a volume of a crank
case varies with reciprocation of pistons.
In the four-cycle engine, an inner space of the crank case
communicates with an inner space of a cylinder head of the engine
through a cam chain tunnel or the like. The breather device allows
the inner space of the cylinder head to communicate with the
outside of the engine through a breather pipe. Or, the breather
device allows an inner space of the crank case to communicate with
the outside of the engine through the breather pipe. The breather
device serves to release a pressure in the crank case resulting
from the reciprocation of the pistons to the outside of the
engine.
When releasing the pressure inside of the crank case to the
outside, the breather device functions to prevent leakage of the
oil mist, included in the released air (blow-by gas), to the
ambient side.
The breather device needs to function so as to prevent the oil flow
from the engine to the ambient side even when the watercraft is
inverted.
Meanwhile, since the personal watercraft is commonly used on the
water and often splashed with water, regular maintenance such as
application of oil is necessary for smooth movement of movable
mechanical elements of a throttle device provided in an intake pipe
or movable mechanical elements of an air-intake port.
SUMMARY OF THE INVENTION
The present invention addresses the above-described condition, and
an object of the present invention is to provide a personal
watercraft capable of preventing oil flow from an oil reservoir to
outside even when the watercraft is inverted. Another object of the
present invention is to provide a personal watercraft capable of
suitably supplying oil from a breather device to movable mechanical
elements of a throttle device provided in an intake passage or
movable mechanical elements of an air-intake port.
According to the present invention, there is provided a personal
watercraft comprising: a four-cycle engine; a water jet pump driven
by the engine, the water jet pump pressurizing and accelerating
water taken in from outside of the watercraft and ejecting the
water from the outlet port to propel the watercraft as a reaction
of the ejecting water; a breather pipe configured such that a base
end is connected to the engine to communicate with an inside of the
engine, an intermediate portion is located lower than the base end,
and a tip end is located higher than the base end; and a breather
box, wherein the tip end of the breather pipe communicates with the
inside of the breather box and the base end of the breather pipe is
located lower than the breather box.
In the personal watercraft so constituted, while the watercraft is
not moving or cruising under an engine-running condition,
air-containing oil (oil mist) flows from the engine toward the
breather box above the engine and is liquefied in the breather box.
On the other hand, when the watercraft is inverted, the
intermediate portion of the breather pipe is located higher than
the base end of the breather pipe communicating with the engine.
Therefore, flow of the oil from the engine toward the breather box
can be prevented.
It is preferable that the base end of the breather pipe is
connected to a breather pipe connecting port provided in a cylinder
head of the engine.
It is preferable that the breather pipe has a branch portion at a
position lower than the base end, and the branch portion
communicates with the inside of a crank case of the engine through
an oil return pipe. Thereby, the liquefied oil reserved in the
breather pipe can be returned to the engine. This is optimal to the
engine, including the oil reservoir provided at the bottom of the
crank case of the engine.
It is preferable that the breather pipe has a branch portion at a
position lower than the base end, and the branch portion
communicates with inside of an oil tank for reserving engine oil
through an oil return pipe. Thereby, the liquefied oil reserved in
the breather pipe can be returned to the oil tank. This is optimal
to the engine of a dry sump type in which the oil tank is provided
independently of the engine.
According to the present invention, there is further provided a
personal watercraft comprising: a four-cycle engine; a water jet
pump driven by the engine, the water jet pump pressurizing and
accelerating water taken in from outside of the watercraft and
ejecting the water from the outlet port to propel the watercraft as
a reaction of the ejecting water; an air-intake passage provided
for the engine and provided with an air-intake box; a breather box
provided in the air-intake passage and including an oil inlet
communicating with inside of the engine; a communicating passage
through which inside of the breather box communicates with the
air-intake passage; and a breather pipe through which the oil inlet
of the breather box communicates with inside of the engine.
In the personal watercraft so constituted, while the watercraft is
not moving or cruising under the engine-running condition, oil mist
can be supplied from the breather box into the air-intake passage
through the communicating passage. The breather box may be provided
in the air-intake box or at a different position in the intake
passage. Also, by providing the air-intake passage over the
cylinder head, the length of the air-intake passage can be
extended. Consequently, an engine with a good inertia effect for
air-intake is attained.
It is preferable that an inlet of the communicating passage is
located as high as or lower than the oil inlet. Thereby, even when
the watercraft is inverted, it is possible to prevent the oil
reserved in the breather box from flowing toward the intake
passage.
It is preferable that the breather pipe is configured such that the
base end is located lower than the breather box, the tip end
communicates with the inside of the breather box and is located
higher than the base end, and an intermediate portion is located
lower than the base end.
The personal watercraft may further comprise: an oil return port
provided in the breather box; a breather return pipe through which
the oil return port communicates with an oil reservoir; and a first
baffle wall provided between the oil inlet and the inlet of the
communicating passage in the breather box, the first baffle wall
extending downwardly from a ceiling wall of the breather box, such
that a lower end of the baffle wall is located lower than an
imaginary line connecting an upper end of the oil inlet to the
inlet of the communicating passage so as to form a space allowing
the oil inlet and the inlet of the communicating passage to
communicate with each other below the lower end of the first baffle
wall.
In the personal watercraft so constituted, while the watercraft is
not moving or cruising under the engine-running condition, the oil
mist flows through the space below the first baffle wall so as to
be supplied from the breather box into the air-intake passage
through the communicating passage, and the oil liquefied and
separated in the breather box can be returned from the oil return
port to the oil reservoir. On the other hand, when the watercraft
is inverted, the first baffle wall serves to prevent the oil
reserved in the breather box from flowing into the air-intake
passage.
The personal watercraft may further comprise: a second baffle wall
provided between the oil inlet and the inlet of the communicating
passage, the second baffle wall extending vertically from a bottom
wall of the breather box, such that an upper end of the second
baffle wall is located higher than the imaginary line connecting
the upper end of the oil inlet to the inlet of the communicating
passage so as to form a space allowing the oil inlet and the inlet
of the communicating passage to communicate with each other above
the upper end of the second baffle wall. With such a constitution,
the oil mist flows above the second baffle wall or above the second
baffle wall and below the first baffle wall so as to be supplied
from the breather box into the air-intake passage. On the other
hand, when the watercraft is inverted, the second baffle wall or
the first baffle wall and the second baffle wall serve to prevent
the oil reserved in the breather box from flowing into the
air-intake passage.
It is preferable that the oil return port is located lower than the
oil inlet.
It is preferable that a throttle body to control air flow in the
air-intake passage is contained in the air-intake box so that part
of oil in the breather box is supplied to the throttle body through
the communicating passage.
The personal watercraft may further comprise an oil return port
provided in the breather box; a breather return pipe through which
the oil return port communicates with an oil reservoir; and a
porous plate provided inside of the breather box, for permitting
flow of oil between the oil inlet and the inlet of the
communicating passage. As defined herein, the porous plate includes
plates through which communication is made between the oil inlet
and the inlet of the communicating passage, such as a mesh plate or
a punching plate.
In the personal watercraft so constituted, while the watercraft is
not moving or cruising during engine running, the oil mist passes
through holes of the porous plate so as to be supplied from the
breather box into the intake passage through the communicating
passage, and the oil separated in the breather box can be returned
from the oil return port into the oil reservoir. On the other hand,
when the watercraft is inverted, the oil reserved in the breather
box can be effectively prevented from flowing into the intake
passage because of the presence of the porous plate. Against the
inversion of the watercraft, the porous plate may be configured to
have an upper portion having no holes, for the purpose of more
effectively preventing the oil flow into the intake passage.
It is preferable that the breather box is integrally provided at a
bottom of the air-intake box and the communicating passage is
formed in a separating wall that defines the air-intake box and the
breather box.
It is preferable that the breather box is integrally provided
inside of the air-intake box and the communicating passage is
formed in a separating wall that defines the air-intake box and the
breather box. This provides a simplified constitution.
It is preferable that the oil return port is located lower than the
oil inlet. Thereby, while the watercraft is not moving or cruising
during engine running, the oil reserved in the breather box can be
quickly returned to the oil reservoir, for example, to the oil tank
or oil reserving portion at the lower portion of the crank case,
through the breather return pipe.
It is preferable that a throttle body to control air flow in the
air-intake passage is contained in the air-intake box so that part
of oil in the breather box is supplied to the throttle body through
the communicating passage. Thereby, the oil mist can be supplied to
the element outside of the throttle body, for example, to a movable
mechanical element such as the throttle mechanism, outside of the
throttle body, for lubricating the element. As a matter of course,
the oil mist can be supplied to the inside of the throttle body
through the opening of the throttle body, thereby lubricating the
movable mechanical element.
The above and further objects and features of the invention will be
more fully be apparent from the following detailed description with
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view showing an engine, an air-intake
box above the engine, and a breather box provided in the air-intake
box, of a personal watercraft according to an embodiment of the
present invention, which is sectioned along the direction
orthogonal to the longitudinal direction of the watercraft;
FIG. 2 is a plan view taken in the direction of arrows
substantially along line II--II in FIG. 1;
FIG. 3 is a partially enlarged sectional view of a structure of the
air-intake box and the breather box in FIG. 1;
FIG. 4 is a side view showing an entire jet-propulsion personal
watercraft according to the embodiment of the present
invention;
FIG. 5 is a plan view showing the entire personal watercraft in
FIG. 4;
FIG. 6 is a partially enlarged cross-sectional view showing another
structure of the breather box;
FIG. 7 is a partially enlarged cross-sectional view showing another
structure of the breather box;
FIG. 8 is a partially enlarged cross-sectional view showing another
structure of the breather box;
FIG. 9 is a partially enlarged cross-sectional view showing another
structure of the breather box;
FIG. 10 is a cross-sectional view showing that a throttle body is
contained in the air-intake box of the personal watercraft
according to another embodiment of the present invention, which is
sectioned along the direction orthogonal to the longitudinal
direction of the watercraft;
FIG. 11 is a partially enlarged cross-sectional view showing an
internal structure of the air-intake box in FIG. 10;
FIG. 12 is a partially enlarged view showing another internal
structure of the air-intake box;
FIG. 13 is a partially enlarged view taken in the direction of
arrows substantially along line XIII--XIII in FIG. 12, showing a
structure of a connecting face between the air-intake box and the
breather box in FIG. 12, and a separating wall provided on the
connecting face to define the air-intake box and the breather box;
and
FIG. 14 is a partially enlarged view showing another structure of
the connecting face between the air-intake box and the breather
box, and the separating wall provided thereon.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, a personal watercraft which is one type of a
jet-propulsion watercraft according to an embodiment of the present
invention will be described with reference to the accompanying
drawings.
In FIGS. 4, 5, reference numeral A denotes a body of the personal
watercraft. The body A comprises a hull H and a deck D covering the
hull H from above. A line at which the hull H and the deck D are
connected over the entire perimeter thereof is called a gunnel line
G. In this embodiment, the gunnel line G is located above a
waterline L of the personal watercraft.
As shown in FIG. 5, an opening 16, which has a substantially
rectangular shape seen from above, is formed at a relatively rear
section of the deck D such that it extends in the longitudinal
direction of the body A. As shown in FIGS. 4, 5, a riding seat S is
provided over the opening 16.
An engine E is provided in a chamber (engine room) 20 surrounded by
the hull H and the deck D below the seat S.
The engine E is a four-cycle engine of a multi-cylinder (e.g.,
four-cylinder) dry sump type. As shown in FIG. 4, a crankshaft 26
of the engine E is mounted along the longitudinal direction of the
body A. An output end of the crankshaft 26 is rotatably coupled
integrally with a pump shaft 21 S of a water jet pump P through a
propeller shaft 27. An impeller 21 is attached to the pump shaft
21S of the water jet pump P. The impeller 21 is covered with a pump
casing 21C on the outer periphery thereof. A water intake 17 is
provided on the bottom of the hull H. The water is sucked from the
water intake 17 and fed to the water jet pump P through a water
intake passage 28. The water jet pump P pressurizes and accelerates
the water by rotation of the impeller 21. The pressurized and
accelerated water is discharged through a pump nozzle 21R having a
cross-sectional area of flow gradually reduced rearward, and from
an outlet port 21K provided on the rear end of the pump nozzle 21R,
thereby obtaining the propulsion force.
In FIG. 4, reference numeral 21V denotes fairing vanes for fairing
water flow behind the impeller 21. As shown in FIGS. 4, 5,
reference numeral 24 denotes a bar-type steering handle. The handle
24 operates in association with a steering nozzle 18 swingable
around a swing shaft (not shown) to the right or to the left behind
the pump nozzle 21R. When the rider rotates the handle 24 clockwise
or counterclockwise, the steering nozzle 18 is swung toward the
opposite direction so that the watercraft can be correspondingly
turned to any desired direction while the water jet pump P is
generating the propulsion force. As shown in FIG. 6, the handle 24
is provided with a throttle lever Lt for controlling an engine
speed of the engine E in the vicinity of a right grip.
As shown in FIG. 4, a bowl-shaped reverse deflector 19 is provided
above the rear side of the steering nozzle 18 such that it can
swing downward around a horizontally mounted swinging shaft 19a.
The deflector 19 is swung downward to a lower position behind the
steering nozzle 18 to deflect the ejected water from the steering
nozzle 18 forward, and as the resulting reaction, the personal
watercraft moves rearward.
In FIGS. 4, 5, reference numeral 22 denotes a rear deck. The rear
deck 22 is provided with an openable rear hatch cover 29. A rear
compartment (not shown) with a small capacity is provided under the
rear hatch cover 29. In FIG. 4 or 5, reference numeral 23 denotes a
front hatch cover. A front compartment (not shown) is provided
under the front hatch cover 23 for storing equipments and the like.
In FIG. 5, To denotes an oil tank provided independently of the
engine E, for reserving oil for engine lubrication.
As shown in FIGS. 1, 2, in the personal watercraft according to the
embodiment of the present invention, air-intake passages Ip is
positioned over a cylinder head Ch of the engine E. As shown in
FIGS. 1, 2, an air-intake box (air filter box) 1 is provided in the
air-intake passages Ip (in this embodiment, at an intermediate
position of the air-intake passage Ip). As shown in FIG. 2, the
air-intake box 1 overlies ignition plugs 6 arranged on the cylinder
head Ch of the engine E. To be precise, as shown in FIG. 2, the
air-intake box 1 somewhat deviates from the cylinder head Ch toward
an exhaust pipe Pe (see FIG. 1) and toward the rear of the
watercraft (upper side in FIG. 2).
Intake pipes 3 respectively constitute the air-intake passages Ip
of the engine E. The intake pipes 3 are configured such that their
tip ends are respectively connected to throttle bodies Vs and their
base ends respectively extend to corresponding intake ports Pi
formed in the cylinder head Ch of the engine E. When the throttle
bodies Vs are at an open position, clean air in the air-intake box
1 is supplied to the intake port Pi of each cylinder head Ch.
Each of the throttle bodies Vs is capable of changing air flow
volume in each air-intake pipe Ip (or intake port Pi) by the
operation of corresponding throttle valve (not shown). The throttle
valve is connected to a throttle lever Lt provided in the vicinity
of a right grip of the handle 24 in FIG. 5 through an operation
cable or wire (not shown). By operating the throttle lever Lt, the
throttle valve of the throttle body Vs is operated, thereby
controlling the engine speed power.
As shown in FIGS. 1, 3, a breather box Bb is provided integrally
with the bottom of the air-intake box 1.
As shown in FIG. 1, the breather box Bb is connected to a breather
pipe connecting port on the engine E side through a breather pipe
Bp. For example, the connecting port is provided in the cylinder
head Ch of the engine E. As shown in FIG. 3, the breather box Bb is
provided with an oil inlet Oi, and a tip end of the breather pipe
Bp is connected to the oil inlet Oi. The breather box Bb is further
provided with an oil return port Or such that the upper end of the
oil return port Or is lower than the upper end of the oil inlet Oi.
As shown in FIG. 3, a base end of a breather return pipe Br is
connected to the oil return port Or. The breather return pipe Br
connects the breather box Bb to the oil tank To (see FIG. 5) as the
engine oil reservoir, as shown in FIG. 1. It should be appreciated
that, when the engine E is not of a dry sump type, a tip end of the
breather return pipe Br is connected to the oil reserving portion
at the bottom of the crank case of the engine E.
As shown in FIG. 1, the breather pipe Bp is entirely substantially
U-shaped. In other words, the breather pipe Bp is configured such
that an intermediate portion of the breather pipe Bp is lower than
a base end portion of the breather pipe Bp connected to the engine
E (cylinder head Ch), for example, the breather pipe connecting
port at the upper end portion of the cylinder head Ch, and a tip
end of the breather pipe Bp is connected to the breather box Bb
located higher than the base end portion connected to the engine
E.
Further, as shown in FIG. 3, a communicating passage Po is provided
between the breather box Bb and the air-intake box 1 to allow oil
mist in the breather box Bb to be supplied into the air-intake box
1 (intake passage) through the communicating passage Po.
As shown in FIG. 3, a lower end Po1 corresponding to an inlet of
the communicating passage Po is opened downwardly at a position as
high as or lower than an upper end Oi2 of the oil inlet Oi. In the
embodiment in FIG. 3, the lower end Po1 of the communicating
passage Po is located as high as the upper end Oi2 of the oil inlet
Oi.
A porous plate, for example a mesh plate Pm, is provided between
the communicating passage Po and the oil inlet Oi. The lower end
Po1 communicates with the oil inlet Oi through the mesh plate Pm.
In this structure, the oil return port Or is provided on the side
of the oil inlet Oi with respect to the mesh plate Pm.
Alternatively, as shown in FIG. 6, a first baffle wall Pj may be
provided between the communicating passage Po and the oil inlet Oi
such that the wall Pj extends downwardly from a ceiling wall Bs of
the breather box Bb. The lower end of the first baffle wall Pj is
located lower than an imaginary line 100 connecting the lower end
Po1 of the communicating passage Po to the upper end Oi2 of the oil
inlet Oi, and the inlet Po1 of the communicating passage Po
communicates with the oil inlet Oi through a space below the first
baffle wall Pj. As shown in FIGS. 7-9, a second baffle wall Pw may
be vertically provided on a bottom surface Bq of the breather box
Bb, adjacently to the first baffle wall Pj. The upper end of the
second baffle wall Pw is located higher than the imaginary line 100
connecting the lower end Po1 of the communicating passage Po to the
upper end Oi2 of the oil inlet Oi, and the inlet Po1 of the
communicating passage Po communicates with the oil inlet Oi through
a space above the second baffle wall Pw. Thus, the provision of the
first baffle wall Pj and the second baffle wall Pw between the
communicating passage PO and the oil inlet Oi creates a labyrinth
structure.
As shown in FIG. 3, the communicating passage Po may vertically
penetrate a separating wall 30 provided to define the air-intake
box 1 and the breather box Bb. Alternatively, the following
configurations are possible. i) As shown in FIGS. 6, 7, the lower
end Po1 of the communicating passage Po may be opened in a side
wall 31 of the breather box Bb and an upper end Po2 thereof may be
opened in an upper surface of the separating wall 30. ii) As shown
in FIG. 8, when the breather box Bb is contained in a corner
portion of the air-intake box 1, a hole may transversely penetrate
a side wall 32 of the breather box Bb as the communicating passage
Po. iii) As shown in FIG. 9, when the breather box Bb is contained
in the corner portion of the air-intake box 1, the communicating
passage Po of a vertically long rectangle shape may transversely
penetrate the side wall 31 of the breather box Bb in the direction
orthogonal to the cutaway surface.
In the personal watercraft so constituted, during engine running,
the oil mist is introduced from the inside of the cylinder head Ch
of the engine E into the breather box Bb through the breather pipe
Bp, and part of the oil mist flows into the air-intake box 1
(air-intake passage) through the communicating passage Po. The oil
mist is supplied to the movable mechanical elements of the throttle
valve and the intake port, or the like, for lubricating them.
During such lubrication, even in the case where the throttle valve
is located in the air-intake passage Ip upstream of the air-intake
box 1 as shown in FIG. 1, the oil mist is supplied to the throttle
valve because the air intake is temporarily blown back when the
intake valve of the engine E is closed.
Since the mesh plate Pm, or the first or second baffle walls Pj, Pw
are provided inside of the breather box Bb, the oil mist makes
contact with these walls and is liquefied. Then, the liquefied oil
is returned from the oil return port Or into the oil tank To as the
oil reservoir through the breather return pipe Br in the dry
sump-type engine, or into the oil-reserving portion at the bottom
of the crank case of the engine E in the engine other than the dry
sump-type engine. In this structure, the oil is supplied by a feed
pump from the oil tank To (or oil-reserving portion) into the
portions requiring lubrication of the engine such as bearing
portion, contact portion between the piston and the cylinder, and
contact portion between a cam and a cam follower, through an oil
filter.
On the other hand, when the watercraft is inverted, the oil does
not flow from the engine E to the breather box Bb through the
breather pipe Bp because of the above U-shaped configuration of the
breather pipe Bp. As described above, the mesh plate Pm or the
first baffle wall Pj is provided inside of the breather box Bb or,
otherwise, the labyrinth structure comprised of the first baffle
wall Pj and the second baffle wall Pw is provided in the breather
box Bb. Further, the communicating passage Po is located as high as
or lower than the oil inlet Oi. For these reasons, the oil reserved
at the bottom of the breather box Bb is prevented from flowing from
the breather box Bb toward the air-intake passage Ip.
As shown in FIG. 10, the throttle body Vs may be contained in the
air-intake box 1. In that case, the oil mist flows from the
breather box Bb into the air-intake box 1 and is supplied into the
air-intake passage Ip through the opening in the throttle body Vs.
Simultaneously, the elements outside of the throttle body Vs
requiring lubrication are lubricated by the oil mist outside of the
throttle body Vs. In this manner, uniform lubrication is effected.
Further, in the structure in FIG. 10, because the throttle body Vs
is enclosed by the air-intake box 1, the throttle body Vs is not
splashed with water even when the seat S is removed. In FIG. 10,
the same reference numerals as those in FIG. 1 are used to indicate
the same or corresponding parts.
Similarly to the embodiment in FIG. 1, as shown in FIGS. 11, 12,
the communicating passage Po may be located as high as or lower
than the oil inlet Oi of the breather box Bb. Or, a baffle wall may
be provided between the oil inlet Oi and the communicating passage
Po. In FIGS. 11, 12, the same reference numerals as those in FIG. 1
are used to indicate the same or corresponding parts, and Pm
denotes a mesh plate.
As shown in FIGS. 11, 12, the air-intake box 1 containing the
breather box Bb, may be divided into two parts such that a
connecting face Fd between them is orthogonal to the intake
passage. In this case, the connecting face Fd defines the breather
box Bb and the air-intake box 1. As shown in FIG. 13, a separating
wall Dv having a communicating passage Po through which the
breather box Bb communicates with the air-intake box 1 is provided
on the connecting face Fd, thereby defining the breather box Bb and
the air-intake box 1. In this structure, assembly and replacement
of parts such as the separating wall Dv, and cleaning of the inside
of these boxes are easily carried out. The structure in FIG. 13 may
be replaced by the wall Dv having the communicating passage Po in
FIG. 14. In FIGS. 13, Pj denotes the baffle wall. In FIG. 11, Bk
denotes a bracket member through which the air-intake box 1 is
mounted to the cylinder head Ch of the engine E.
In the above embodiment, the breather box is provided in the
air-intake box. Alternatively, the breather box may be provided in
the intake pipe, for directly supplying the oil mist from the
breather box into the intake pipe.
As indicated in FIGS. 1, 10 by the dashed lines formed by
alternating long dashes and two short dashes, a branch portion Bp1
is provided at the lower portion of the U-shaped breather pipe Bp
and the oil return pipe Pr is connected to the branch portion Bp1
to allow the liquefied oil in the breather pipe Bp to be returned
to the engine E or the oil tank To as the oil reservoir.
Numerous modifications and alternative embodiments of the invention
will be apparent to those skilled in the art in view of the
foregoing description. Accordingly, the description is to be
construed as illustrative only, and is provided for the purpose of
teaching those skilled in the art the best mode of carrying out the
invention. The details of the structure and/or function may be
varied substantially without departing from the spirit of the
invention and all modifications which come within the scope of the
appended claims are reserved.
* * * * *